Danny Welbeck headed home a late winner as Arsenal beat Southampton at the Emirates Stadium to leave the visitors in the Premier League bottom three.
Charlie Austin came off the bench to equalise for Saints with his first touch after Shane Long's earlier effort had been cancelled out by goals from Pierre-Emerick Aubameyang and Welbeck.
But Welbeck was on hand to score a second of the afternoon and secure a 3-2 win for Arsenal - who have won six games in a row for the first time this season - as a fiery end to the game saw both sides finish with 10 men as Jack Stephens and Mohamed Elneny saw red.
This was the clearest indication yet that Arsene Wenger is now prioritising the Europa League over the Premier League as he made seven changes from Thursday's win over CSKA Moscow, with Jack Wilshere and Mesut Ozil on the bench and Laurent Koscielny and Aaron Ramsey rested completely.
Southampton had the best of the early chances, Dusan Tadic drifting in behind before picking out James Ward-Prowse, who could not mark his 200th Saints appearance with a goal as his effort was cleared off the line by Hector Bellerin.
Mark Hughes saw his side take a deserved lead as Tadic fed Cedric out wide, with the full-back's low cross to the near post left by both Petr Cech and Skhodran Mustafi allowing Long to nip in between the pair and sweep home his first goal since January 2.
Arsenal were misfiring until Aubameyang started and finished a flowing move with a deft finish past the onrushing Alex McCarthy following Welbeck's inventive flick - the Gabon striker having now scored six goals in his first eight league games.
The equaliser brought a shift in momentum, and Welbeck failed to make telling contact with a Granit Xhaka corner before Calum Chambers' acrobatic attempt was smothered by McCarthy.
Welbeck put the hosts ahead as he collected Alex Iwobi's slide-rule pass before cutting inside and seeing his shot deflect in off the heel of Maya Yoshida. It was the England forward's first league goal since September.
McCarthy had to be alert at the start of the second half to make smart saves from Aubameyang and Xhaka with Iwobi also drawing another stop as Arsenal looked to kill off the game.
Saints' chances were limited, but Elneny had to be on hand to clear off the line as Wesley Hoedt sent a header towards goal with Cech scrambling to tip a Long header behind soon after.
Long was celebrating a second of the afternoon only to see the goal rightly chalked off for offside as he steered Cedric's drive past Cech.
Saints were starting to come back into the contest and Cech was on hand again to keep out a long-range Hoedt strike as Gunners boss Wenger reacted by introducing Wilshere and Alexandre Lacazette from the bench.
Hughes, meanwhile, turned to Austin and was instantly rewarded as the striker turned home the equaliser with his first touch after strong work from Cedric.
Welbeck passed up a fine chance to put Arsenal back ahead as he turned Wilshere's pull-back high and wide before Austin bustled through at the other end to poke straight at Cech.
After his great chance moments earlier, Welbeck made amends by heading Arsenal in front for a second time, rising highest at the back post to meet Iwobi's cross.
The contest ended in farce as Stephens was given his marching orders for pushing Wilshere to the ground, with Elneny also sent off in stoppage time for raising his hands following an altercation with Cedric.